Triethylene glycol diheptoate



Patented Dec. 10, 1946 UNITED STATES PATENT OFFICE.

TRIETHYLENE GLYCOL mnnr'roa'rn Leonard Nicholl, 'Nyack, and William P.'Bitler, Haverstraw, N. Y., assignors to Kay-Fries Chemicals, Inc., West Haverstraw, N. Y., a corporation of New York No Drawing. Application November 16, 1943,

Serial No- 510,570

' This invention relates to plasticizers for synthetic rubber, and to the compounds and methods of. producing same.

Inthe utilization of the newly developed synthetic rubbers or elastomers, it has been found necessary to incorporate plasticizing agents therewith in order to improve their workability and wearing qualities. As there are a number of groups of compounds utilized as synthetic rubbers, there are plasticizing problems inherently different for each group of compounds.

The improvements of the present application are directed to the use of plasticizers particularly suited for work'with butadiene-acrylonitrile copolymers and comprising heptaldehyde products,

erature so far as is now known. The two compounds are derived from a series of reactions which are interdependent, and which comprise.

(1) condensation of heptaldehyde to heptyl heptoate; (2) reaction of the heptyl heptoate produced under (1) with triethylene glycol and heptanol to form triethylene glycol diheptoate; (3) recovery of excess heptanol and reaction of same with phthalic anhydride to produce diheptyl ,phthalate.

In the carrying out of the reactions indicated generally above, special results are obtained by the use of aluminum alkoxides as catalysts. By the use of the processes herein and using dry aluminum alkoxides as catalysts, it has been found possible to treat crude heptaldehyde (oenanthal),containing 75 to 90% of heptaldehyde, when the crude aldehyde, which normally contains higher organic acids, acrolein and water, is freed from acrolein and water. The crude heptaldehyde, which is usually derived from castor oil, is distilled to remove the acrolein, and then the water, leaving ,the heptaldehyde and the higher organic acids as a residue. By this treatment, and with this discovery, the preparation of a pure heptaldehyde as a starting material for the condensation is not required. It

is to be noted that in order to obtain maximum yields from the pure heptaldehyde that the aerolein must be removed or it wil1 interfere with 65 iodine. The still is closed, the condenser being 1 Claim. (Cl. 260-488) the main condensation reaction and lower the yield of heptyl heptoate. The water present in the crude heptaldehyde is also required to be removed because it would hydrolyze the aluminum alkoxide catalysts, and thereby prevent the condensation reaction from taking place, or it would cause the yield of heptyl heptoate to be lowered to a very considerable extent.

The several processes involved in the, preparation of the necessary reagents and the carrying out of the condensation reactions, will now be described:

Stripping of crude heptaldehyde Crude heptaldehyde is stripped to remove acrolein and water in the following manner:

3,080 lbs. of crude heptaldehyde are loaded into a colunm still, together with 15 lbs. of tartaric acid. The distillation is conducted with a. liquid temperature of 110 C. and a vapor temperature of C'., the distillation at the end being carried out undeng. vacuum. of 180 mm. to The distillant or still residue is cooled to room temperature and drawn off into dry containers which are protected from ingress of moisture. The yield should be approximately 2860 lbs. of stripped crude heptaldehyde of 88% strength equivalent to approximately 2500 lbs. of 100% heptaldehyde.

Preparation of catalysts I As the aluminum .alkoxide catalyst, either-aluminum butoxide or aluminum heptoxide may be used. These catalysts are prepared as follows:

Aluminum butoaqide.A thoroughly dried still is loaded with a charge comprising 225 lbs. of

V butanol, 28.6 lbs. of aluminum, and 0.28 lbs. of

iodine. The still is provided with a moisture trap, and thecondenser column is open to the air. The reaction mixture is heated, while stirring, until the reaction becomes vigorous and refluxing takes place. 'If necessary, the reaction'may be controlled bycooling the still. When the reaction has been brought under control, an additional 230 lbs. of butanol is added, as rapidly as possible, while still controlling the reaction with cooling water. After all the butanol has been added, which will take approximately one hour,

and the reaction has subsided, the still is heated for one hour longer at 90 to C. to complete the reaction. This will give a solution of aluminum butoxide in an excess of butanol.

Aluminum heptorida-Into-a thoroughly dryv still there is loaded a charge comprising 715 lbs. heptanol, 28.6 lbs. of aluminum, and 45oz. of

3 4 left open, and provided with a moisture trap. Preparation of trieihulene ulycol diheptoate The reaction mixture is refluxed at 160 C. (col- (B. P. ca. 250-255 C. at 2 mm.) umn temperature) for 1 hours, with good agitation. At the end of the reaction time, the re- In the preparation of this comp re i action mixture is allowed to cool to room tem- 5 a straight ester exchange, pp to a w perature. reaction between heptyl heptoate (or butyi hep- In addition to the specific aluminum alkoxides toate a d h t l h t at a d tr thy ene disclosed, it has also been found that other alu- 8 8 with So um t o de being used as minum alkoxldes and other alcohols will work. t ys There are tw eth ds of arry n out Thus, aluminum ethoxide in an excess of ethanol 10 s rea tion depending on whether heptyl hepgives desirable results as a catalytic mixture. toate is used, or the mixture of butyl ptoate Condensation of stripped, crude hepialdehyde :53 .225% gsgf ggg These Separate reactmns Using aluminum butomide as a catalyst-2860 Using a mixture of butt/l heptoate and heptyl lbs. of stripped. crude heptaldehyde are added heptoate.-Into a thoroughly y- Still there is to the aluminum butoxide catalyst. The mixture charged 768 lbs. of triethylene glycol and 370 is well agitated over a period of one hour, and lbs. of sodium ethoxide in anhydrous ethyl alcothe temperature is maintained at 26-30 C., by hol solution (containing 6.5% sodium). The the use of cooling water on the still jacket, and reaction mixture is heated to 100 C. and the by controlling the rate of addition of the crude alcohol liberated is distilled oil to a liquid temheptaldehyde to the still. When the heptaldeperature of 110 C. To remove the residual alcohyde has been completely added, the reaction is hol a vacuum of 35 mm. may be pulled on the continued for another four hours at the same still. To the dealcoholized reaction mixture there temperature. The reaction mixture is then fracis charged a mixture of 1560 lbs. of heptyl heptionated according to the following schedule: toate and 615 lbs. of butyl heptoate. The temiweight 0mm), 3,240 perature of the reaction mixture is raised to 132- 135 C. under a vacuum of 60-65 mm. Butanol mm vm distllls over at a still-head vapor temperature of te i teglp m" gi 3 Remarks 60-65 C. The liquid temperature will have-tube raised to 145-l55 C. in order to remove the residual butanol. Thereafter the vacuum is in- 50 5H0 ii' Bum creased slowly to 10 mm., and the temperature 61-82 91 Int. cut. of the reaction mixture reduced to 125-130 C. gfj ga 58 354 Heptanol. The heptanol set free in the reaction will start 20-3 600 Butylheptoabe p to distill over at a vapor temperature at approx- MHGO 17 1,530 Hepmheptom. imately 78-79" C. The vacuum distillation of 55o Residue. heptanol is continued while gradually raising the liquid temperature to a final value of approxi- The reaction should be carried out within the mately After Temva1 of the heptaml temperatures stated, as it has been found that, 40 the reaction mixture is allowed to cool, and is at higher temperatures, such as 40 C., the yield then washed with it to A of its volume of 15% fresh catalyst, decolorize the reaction mixture. The aqueous is cut by approximately 10%. Th t tal ti of sulphuric acid and at a temperature of 60'70 reaction should approximate five hours, although until it is neutral O y S y acidhe it may be extended to fourteen hours, or more, washed oilis permanganate treated in dilute acid providing the temperature limits are not exsolution, using 1% of the weight of the reaction 1 ceeded. A second condensation can be run in mixture of permanganate 1n 50111151011- the same still, merely requiring the draining ofl Upon completion of this treatment a slight excess of the used catalyst and replenishment with of sodium bisulp e Solution 18 added to Using aluminum heptoxide as a. catalyst- 5o layer is separated from the oily layer and washed reaction is conducted under substantially the with Water until free from y soluble a s same conditions and limitations as applied to ese salt. The treated oil is further treated with the use of aluminum butoxide. The stripped, 1/2% Nuchar (decolorizmg carbm) blown dry,

' crude heptaldehyde (2860 lbs.) is added to the and filteredaluminum heptoxide catalyst and the mixture Using hept1/lheptat- A charge 01 12301b$- well stirred. The reaction mixture is maintained triethyene glycol and 570 sodium ethoxide at 26-30" C. by cooling the still, and by co in absolute alcohol solution (containing 6.5% soling the rate of addition of the heptaldehyde. dium) are loaded into a thoroughly dry still- When all the heptaldehyde has been added, th The reaction mixture is heated to C., and reaction is continued, at the same temperature, 60 ethanol distilled oflf to a liquid temperature of for a time period of four hours. The reaction C. A final vacuum of 35 mm. is usually mixture is then fractionated according to the required to be pulled on the still in order to get following data: the last traces oi alcohol over. To the dealco- [Weight oi batch 340 g.)

Wt. low Wt. Wt. oi Wt boll heptyl Remarks traction mm heptanol heptome 1s. 7 13.7 Impurities in crude heptaldehyde.

55 55 Heptanol. 7.5 4.5 3.0 Int. cut. 219 219.0 Heptyl heptoete. 12.0 12.0 End cut heptyl heptoaie. 33.2 Residue.

indicated immediately above.

Preparation of diheptyl phthalate In this process phthalic anhydride is esterifled with heptanol in the following manner. Into a still there is charged 3380 lbs. of hepta'nol, 2160 The temlbs. oi phthalic anhydride and 27.7 lbs. of concentrated sulphuric acid. The reaction mixture is raised to a temperature of 125-130" 0., when water should begin to distill over, at normal pressure. The reaction mixture is maintained at substantially constant temperature, and a vacuum, up to mm., is applied, in order to maintain the distillation. Any heptanol distilled over I with the water is separated and returned to the reaction mixture, so that the amount of heptanol in the reaction mixture is maintained substantially constant. This is continued until the reaction is completed and no more water distilled over. The completion of the reaction is tested so that one cc. of the reaction mixture is equivalent to approximately 3 cc. of N/10 NaOH.

When the reaction mixture has dropped to a temperature of 60-7 0 0., it is washed with dilute (540%) sodium carbonate solution, until slightly alkaline. The mixture is then permanganate treated with {a of its weight of potassium permanganate, in a 2% solution, under slightly acid conditions. Manganese dioxide is precipitated out, and is dissolved in a slight excess of 35% sodium bisulphite solution. The washed water layer is separated, and the reacted mixture'asain washed with water, until free from soluble mariganese salt. The washed product is then treated,

with decolorizlng carbon, blown dry, and filtered.

The compounds, triethylene glycol diheptoate and diheptyl phthalate are novel and useful and are prepared from an originally crude product, namely, heptaldehyde, which is stripped to remove water and acrolein, both of which compounds have a. deleterious eflect on the condensation reactions here involved. Ordinarily, in making a series of condensations, heptanol will not be available to make the aluminum heptoxide catalyst. However, heptanol is produced in the triethylene glycol diheptoate reaction. Consequently butanol must be used for the first condensation (Equation 2) and the heptanoli'ormed inthis reaction may be used to make the desired catalyst. When butanol is used, a mixture 01' butyl heptoate and heptyl heptoate is formed, instead oi the plain heptyl heptoate, which is iormediwhenheptanol alone is used to make the catalyst. Where the mixed heptoates are used, there is produced a mixture 01' heptanol and butanol, which as shown above, are'readily separatedand recovered by fractionation.

The reactions involved in the above described processes may be graphically illustrated by the following equations:

Condensation of heptaldehudc With aluminum heptoxide as catalystr iii-heptoxide in 1 (1) 2CHs(CH|)|CHO CHiwHmC O O CH (CH;);OH| Y excess of heptanol (Heptaldehydc) (Heptyi heptoate) Al-butoxide in --o excess oi butanol (Heptaldehyde) (Butyl heptoa te) OHI(CHI)ICOOOHI(CHI)2Q HI CHatOHzhCOOCHKOHrhCH: EOCHKCHshCH:

. (Hept'yl heptoate) (Heptanoi)- Preparation of Triethylen plycol diheptoate by ester exchange With heptyl heptoate: I

4) zomwmncoocniwmhom Q 2 I HOCH! 1 0 a) zoniwnmcooemwmtom 35; 8g; aomwemcmoa I (Hep'tyl heptoate) 8 8 (heptanol) HO OH: CHKCHghCOOCH:

(Trlethylene Trieth lene col 7 glycol) with butyl heptoate: HO-CH1 CHs(OH COOCHs H:

H, $3. mniwncionion I (Butyl heptoate) I (Butanol) AH: {EH HO-JJH; cmd'irm cooHr T1! 111 T fll zi wb iimb e'i i 7 8 With mixed butyl heptoate and heptyl heptoate:

HOCH: CHKGMICOOCH:

Hg H: (5) cmwmncoocmwmncn, J)

(Heptyl heptoate) I H: H!

H. 1 cmwnmcmoa crmcnmcmon I cmwm coocmwmhcm g (au i m; (Heptmol) (B m mm V uty p Hg 43H;

no HI, cmwnmcooom (Trlethylene (Triethylehe glycol I glycol) diheptotte) Preparation 0; diheptyl phthalate a) 0-0 /0 c ocmwmncn,

0 2OHx(CHr)|( CH|OH) 0 H20 I (Heptanol (Water) 0 0 from Equation 2) 0-0 CH1(CH1)|CHQ Phthsli Dih t 1 h h a hydrld 9p y p t 81m) stripped to remove interfering components and has been provided novel plasticizers for synthetic reactions carried out in the presence 01' non-inelastomers, and particularly derivatives of buterfering residues. tadiene-acrylonitrile type in which desirable 30 What is claimed is: "low temperature flexibility is imparted to the Triethylene glycol diheptoate. elastomers. It will also be appreciated that there LEONARD NICHOLL.

has been provided novel method of preparing the plasticizers in which a crude product is WILHAMRBI'IIER.

It will now be appreciated that there 

